Deletion of Ptp4a3 reduces clonogenicity and tumor-initiation ability of colitis-associated cancer cells in mice

Abstract

The PTP4A3 gene is highly expressed in human colon cancer and often associates with enhanced metastatic potential. Genetic disruption of the mouse Ptp4a3 gene reduces the frequency of colon tumor formation in mice treated in a colitis-associated cancer model. In the current study, we have examined the role of Ptp4a3 in the tumor-initiating cell population of mouse colon tumors using an in vitro culture system. Tumors generated in vivo following AOM/DSS treatment were isolated, dissociated, and expanded on a feeder layer resulting in a CD133+ cell population, which expressed high levels of Ptp4a3. Tumor cells deficient for Ptp4a3 exhibited reduced clonogenicity and growth potential relative to WT cells as determined by limiting dilution analysis. Importantly, expanded tumor cells from WT mice readily formed secondary tumors when transplanted into nude mice, while tumor cells without Ptp4a3 expression failed to form secondary tumors and thus were not tumorigenic. These results demonstrate that Ptp4a3 contributes to the malignant phenotype of tumor-initiating cells and supports its role as a potential therapeutic target to inhibit tumor self-renewal and metastasis.

Molecular Pathways: Targeting Protein Tyrosine Phosphatases in Cancer

“…Depletion of PTP4A3 reduced TNBC tumor growth in vivo by reducing proliferation marker (Ki67), phospho-ERK1/2 and p38 levels, while increasing apoptotic markers (1). Highly elevated PTP4A3 expression is also associated with enhanced tumor formation and metastasis by reducing tumor initiating cells in colon cancer mouse models (46). Collectively, these studies demonstrate that oncogenic PTPs play a critical role in tumor initiation, progression and metastasis by enhancing signaling pathways and serving as valuable targets for cancer therapy.…”

A chemical genetics approach identifies PTP4A3 as a regulator of colon cancer cell adhesion

“…Mouse CRC cells were derived from our previously described primary colon tumor epithelial cells, which were obtained from Ptp4a3 fl/fl mice treated with azoxymethane and dextran sodium sulfate (34). Mouse CRC cells were initially plated on a confluent feeder layer of lethally irradiated (80 Gy) LA7 rat mammary tumor cells (CRL-2283; American Type Culture Collection, Manassas, VA, USA) at ;80,000 cells/cm 2 and in DMEM/F12 medium with 0.5% fetal bovine serum (FBS), 25 mg/ml gentamycin (MilliporeSigma, St. Louis, MO, USA), and 1% insulin-transferrin/selenium (Mediatech, Manassas, VA, USA).…”

“…Mouse CRC cells were initially plated on a confluent feeder layer of lethally irradiated (80 Gy) LA7 rat mammary tumor cells (CRL-2283; American Type Culture Collection, Manassas, VA, USA) at ;80,000 cells/cm 2 and in DMEM/F12 medium with 0.5% fetal bovine serum (FBS), 25 mg/ml gentamycin (MilliporeSigma, St. Louis, MO, USA), and 1% insulin-transferrin/selenium (Mediatech, Manassas, VA, USA). When cells reached ;70% confluence, Ptp4a3 fl/fl cells were detached from the feeder layer by incubation with Earle's balanced salt solution/1 mM EGTA/1% HEPES followed by 0.25% trypsin/0.1% EDTA as previously described (34). A mouse CRC feeder layer-independent cell population was generated by serially decreasing the feeder layer at the time of passaging (approximately once per week with a 20% reduction in number of cells in feeder layer) and increasing the FBS concentration (15% increase in concentration at time of passage).…”

“…When exposed to a carcinogen in a widely used model of colitisinduced CRC (33), Ptp4a3-null mice developed fewer tumors than wild-type mice. When CRC cells were isolated from the tumors of Ptp4a3 wild-type and Ptp4a3-null mice and cultured on a lethally irradiated rat cell feeder layer, Ptp4a3-null cells produced fewer in vitro colonies by limited dilution analysis and subcutaneous tumors than cells isolated from Ptp4a3 wildtype mice (34). Conclusions obtained with these 2 cell populations should be viewed with caution, however, because the isolated CRC tumor cells were exposed to a mutagen and may harbor other independent genetic differences.…”

LIN28B Activation by PRL-3 Promotes Leukemogenesis and a Stem Cell–like Transcriptional Program in AML

“…PRL-2 has been reported to increase EPO and IL3 response in hematopoietic cells (32) and play critical roles in regulating HSC self-renewal (33). A previous study reported that genetic disruption of PRL-3 reduces clonogenicity and growth of CD133 þ mouse colon cancer cells in an in vitro culture system (34). CD133 is also a specific marker for human hematopoietic stem/progenitor cells (35,36).…”